function showNumberWithAnimation(i, j, randNumber) {
    var numberCell = $("#number_cell_" + i + "_" + j);
    numberCell.css({
        "background-color": getNumberBackgroundColor(randNumber), //当numberCell从没有数字变到有数字，或者从一个数字变成另一个数字时，该numberCell的css样式要发生改变
        "color": getNumberColor(randNumber)
    });
    numberCell.text(randNumber);

    numberCell.animate({
        "width": "100px",
        "height": "100px",
        "top": getPosTop(i, j),
        "left": getPosLeft(i, j)
    }, 50);
}

function showMoveAnimation(fromx, fromy, tox, toy) {
    var numberCell = $("#number_cell_" + fromx + "_" + fromy);
    numberCell.animate({
        "top": getPosTop(tox, toy),
        "left": getPosLeft(tox, toy)
    }, 200);
}

function updateScore(score) {
    $("#score").text(score);
}